Prior devices for monitoring speed and direction of movement have required a mechanical or electrical connection to the monitored object which is not necessary in the present invention disclosed herein.
A device disclosed in British Pat. No. 1,306,699 is a partial advance in the art, but it still requires some mechanical connection to whatever is being monitored. It requires a special electrically conducting rotary wheel, for example, mechanically coupled to the vehicle wheel or other object that is being monitored. It cannot determine direction of motion, linear movement of any kind, nor rotary velocity, but only rotary acceleration or deceleration. The present invention can monitor and determine all such movements. The present invention does not require a similar rotary wheel, or any equivalent element at all. It is also adapted to take advantage of the special complex characteristics of an alternating voltage source as explained below, in contrast to the direct voltage source utilized in the British patent.